Technique for the continuous production of an expanded metal strip

ABSTRACT

A lead strip that is passed in shearing contact with the shearing edge of a metal-expanding machine so that only part, but not all, of the transverse extent thereof is expanded, and the remaining portion retains its non-expanded character. The nonexpanded area is oriented lengthwise of the strip along one side edge, to which pulling forces or the like may be readily applied to the strip without distorting or otherwise adversely affecting the expanded portion of the strip.

United States Patent 1191 Borello [111 3,913,193 14 1 Oct. 21, 1975 1 TECHNIQUE FOR THE CONTINUOUS PRODUCTION OF AN EXPANDED METAL STRIP [76] Inventor: Domenic Borello, 142 Nyack Ave.,

' Pelham, NY. 10803 22 Filed: Apr. 17, 1974 21 Appl. No.: 461,615

3/1928 Dean 29/61 11/1967 Johnson ..29/6.l 10/1974 Watanabe 2.9/6.1

Primary ExaminerJ. M. Meister Assistant Examiner-Leon Gilden Attorney, Agent, or FirmBauer & Amer [57] ABSTRACT A lead strip that is passed in shearing contact with the shearing edge of a metal-expanding machine so that only part, but not all, of the transverse extent thereof is expanded, and the remaining portion retains its nonexpanded character. Thenon-expanded area is oriented lengthwise of the strip along one side edge, to which pulling forces or the like may be readily applied to the strip without distorting or otherwise adversely affecting the expanded portion of the strip.

1 Claim, 4 Drawing Figures U.S. Patent 0m. 21, 1975 FIG/ o o I.

o v o 0.

F IG.2b PRIOR ART 532 F1620 PRIOR ART TECHNIQUE FOR THE CONTINUOUS PRODUCTION OF AN EXPANDED METAL STRIP The present invention relates to an improved technique for economically producing or converting a metal strip, preferably lead, into an expanded state in which the major portion thereof is expanded and there is also one non-expanded portion oriented lengthwise of the strip.

It is already well known how to produce expanded metal, one such preferred apparatus for achieving this result being described in U.S. pat. No. 3,280,446, issued on Oct. 25, 1966. As generally understood, the process contemplates the feeding of a metal strip from a supply roll beneath a shearing edge which shears the strip at spaced locations. Specifically, during such shearing, the portions of the strip adjacent the shearing cut are expanded or elongated to produce a pattern in the metal which consists of criss-crossing strands which bound diamond shaped openings. This type of working of metal, namely, converting a solid metal strip into an expanded state consisting of the aforesaid intersecting strands and openings, provides an end product having high degree of utility. For example, an expanded lead plate is highly desirable for use in the manufacture of batteries, the plate in question serving effectively as a negative electrode which is readily operatively arranged along with other such plates in the electrolyte. However, before such use is made of the expanded lead plate, it is necessary to apply various chemical compositions on the same or otherwise treat the plate which, in turn, requires dipping or otherwise feeding the plate through the chemical composition in question.

It would, of course, be most desirable if the aforesaid handling of the expanded product could be achieved using feeding rollers and other such efficient materialhandling equipment, but it unfortunately has been found that the pulling forces applied to an expanded product often change the size of the openings therein and in other ways adversely affect the product. Thus, the only expanded lead plates which heretofore could be effectively handled during the coating thereof had to be individually fabricated prior to such coating, since during their individual fabrication select nonexpanded areas are left to permit proper gripping and handling of the product. However, this individual fabrication of expanded battery plates entails significant handling and preparation costs.

Apparently as an improvement on the foregoing, the patent literature, as exemplified by the patents to HITT, U.S. Pat. No. 1,195,221 and U.S. Pat. No. 1,231,888, discloses a continuous method of producing an expanded metal strip which has a non-expanded portion. According to the method of this prior art, the strip is provided with longitudinally oriented slits, and subsequently these slits are pulled apart into openings to achieve an expanded construction in the strip. While this method is continuous, it contemplates two steps, i.e., a slitting operation followed by an expanding operation, and thus it is still not entirely satisfactory as an economical mass production method.

Broadly, it is an object of the present invention to provide an improved technique for converting a lead strip into expanded and non-expanded portions overcoming the foregoing and other shortcomings of the prior art. Specifically, it is an object to provide a method of converting only a portion, but not all, of the body of the strip into an expanded construction, and thus obtain in the adjacent portion a solid border oriented lengthwise of the strip. Further, in providing the expanded construction, use is made of shearing apparatus in a unique, essentially one step operation which contributes to economical mass production of expanded battery plates produced from the strip.

Further features and advantages of the present invention will become apparent from the following description of several embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a plan view of the improved expanded product hereof which consists of an expanded medial portion having non-expanded peripheral edges;

FIGS. 2A and 2B are views: illustrating the prior art techniques of producing a suitable expanded plate for battery manufacture. Specifically, FIG. 2A illustrates a prior art technique for producing an expanded metal strip also having non-expanded portions, but wherein the non-expanded portions are oriented transversely of the strip. FIG. 28 illustrates an individual expanded plate which is obtained from the strip of 2A and which has to be individually coated and processed preparatory touse in battery manufacture; and

FIG. 3 diagramatically illustrates the manner in which the improved expanded metal product according to the present invention is produced, the illustrated product being characterized by a non-expanded border along one edge.

Reference is now made to the drawings and in particular to FIG. 1 wherein there is shown an expanded metal strip, generally designated 10, which will be understood to consist of lead. Naturally, strip 10 may consist of other shearable metal, but lead has been selected since the invention will be described in connection with battery manufacture. Thus, the selection of lead is not intended to be a limitation on the scope of the invention. Strip 10 will be understood to have a considerable length and, as illustrated, consists of a medial portion, generally designated 12, which in its typical form as an expanded product consists of :a plurality of intersecting strands, individually and colllectively designated 14, which bound pluralities of diamond-shaped openings, herein individually and collectively designated 16. Most important, and constituting the significant structural feature of the strip 10 as. far as the present invention is concerned, is the existence of a non-expanded border area 18 along the edge of the strip 10. If desired, the border area 18 can be produced to extend the entire length of the strip 10.

The existence and the aforesaid orientation of the border area 18 are significant since they permit pulling forces 22 of considerable magnitude to be applied to the strip 10 without adversely affecting and causing any distortion in either the strands 14 or openings 16. Thus, strip 10 can be readily pulled through dipping tanks or otherwise conveniently handled during the coating thereof in preparation of the strip 10 for battery manufacture.

After the necessary handling steps are achieved, it is a simple matter to sever the strip transversely, as at 24 and 26, to produce the individual battery plates. It is significant, however, that prior to said formation of individual sized plates that the strip 10 has already been coated and treated in its continuous, elongated form and, as such, provides economies which are consistent with mass-production techniques.

In contrast to the foregoing, in the production of a typical prior art battery plate, such as is designated 28 in FIG. 2B, the same is individually handled during coating and other preliminary processes. That is, plate 28 is dip-coated or otherwise treated in the form illustrated, rather than while a length portion of a much larger elongated strip, as exemplified by strip of FIG. 1. The reason for this is that plate 28 is derived from the prior art strip 30 of FIG. 2A which, as will now be pointed out, is not conveniently handled in strip form.

Strip 30 is one which is moved in a feed direction 32 beneath a vertically reciprocating shearing edge or implement 34. Operating in a well understood manner, the shearing edge 34 is effective in producing in the metal an expanded state or condition generally designated 36.

When the strip 30 is intended for battery manufacture, it is the prior art practice to temporarily discontinue the operation of the shearing edge 34 at selected intervals along the length of the strip 30 so as to produce the non-expanded portions 38 and 40 which, as clearly illustrated in FIG. 2A, are oriented transversely of the strip 30. Since the non-expanded portions 38 and 40 are transverse, they do not prevent distortion in the expanded portions 36 of the strip if the strip is subjected to a force applied in the feed direction 32. Thus, preparatory to dip-coating or otherwise treating the strip 30, it is necessary to transversely sever the strip 30, as at 42 and 44, and thereby produce the previously noted individual plate 28 of FIG. 2B which is then individually prepared for battery manufacture.

Reference is now made to FIG. 3 illustrating an improved technique according to the present invention of producing the improved expanded strip 10 of FIG. 1 which, as noted, is well suited to the facilitated handling of the entire expanded metal strip, as by applying pulling forces 22 to the strip, without having any adverse affect on the expanded metal portion by way of distortion of the strands or openings thereof. Specifically, as clearly illustrated in FIG. 3, the improved strip 10 is appropriately unwound from a supply roll (not shown) and fed in an oblique angular direction relative to the shearing edge 34. Assisting in this angular direction of feed 32 may be any suitable feeding apparatus, such as a pair of feeding rollers 46 and 48 operatively arranged on opposite sides of the strip 10 and a guiding edge 50. The significance of the oblique angular feed direction is that the edge portion designated 52 in FIG. 3 which ultimately becomes the previously noted nonexpanded border 18 of the improved strip 10 proceeds along a feed path in which it never comes into shearing relation with the vertically reciprocating shearing edge 34. That is, only the portion 54 which exists below the edge portion 52 actually comes in contact with the shearing edge 34 and, as a consequence, is expanded by this shearing edge into what was previously noted as the expanded portion 12 of the strip 10. In this regard, it will be further noted that the size or transverse extent of the expanded section 12 is larger than the strip portion 54, this difference in size of course being due to the expansion caused in the metal by the shearing action of the shearing edge 34. This increase in size occurs in a progressive manner starting at the point of first contact, as at 56, and increasing until the entire portion 54 is expanded which occurs at point 58. Beyond point 58, the improved strip 10 is uniform in its transverse dimension as far as the expanded portion 12 is concerned. Of course, the non-expanded border 18 is uniform throughout.

Following the production technique illustrated in FIG. 3, the resulting strip 10 having an expanded portion 12 and an adjacent nonexpanded border 18 is then readily pulled or otherwise urged through movement by forces applied lengthwise thereof through dip tanks or other treatment apparatus preparatory to the conversion of the strip 10 into a form required for the production of battery plates. When strip 10 has been placed in this condition or form, it is a relatively simple matter to cause severing of the strip, as along the previously noted transverse locations 24 and 26, and thereby convert the strip 10 into appropriately sized battery plates.

Still referring to FIG. 3, it will be understood that any oblique angular orientation of the strip 10 is relative to the vertically reciprocating shearing edge 34 is possible and that any particular angular orientation may be selected from a wide range of angles 59. By and large, the angle selected will be dictated by the width of the individual strands 14 that are required and also the size of the openings 16 that are required. Satisfactory results have been achieved with a lead strip 10 6 inches wide by feeding the same past a shearing edge 34 oriented at an angle of 20 to the path of movement of the strip. The resulting product has a non-expanded border% inch wide, strands 14 which are three-thirty seconds inch wide, and openings 16 which at their widest point are three-eights inch.

In summary, the technique illustrated in FIG. 3, namely that of feeding the supply length of the strip 10 in oblique relation to the shearing edge 34, effectively results in the production of a final product in which there is both expanded and non-expanded portions and in which, most significantly, the non-expanded portion is oriented lengthwise of the strip. In the production of this unique product, the feeding of the strip 10 in the angular direction 32 has two significant contributions. First, it provides an aspect of feed movement in the direction 60 which is necessary to move the strip 10 up to, beneath, and then away from the shearing edge 34. Second, it provides a degree of freedom of movement in the direction 62 which is necessary to allow for the basic expansion or elongation in the metal strands 14 which, of necessity, occurs during the conversion of the solid metal into an expanded state. Thus, the technique herein disclosed effectively permits the production of an expanded metal product having the noteworthy structural attributes of strip 10 of FIG. 1 and is consistent with the requirements for effectively converting metal from a solid to an expanded state.

To better understand the significance of the availability of the degree of expansion movement 62 to the ability to produce the strip 10 of FIG. 3, reference should be made to the enlarged scale portion of FIG. 3 which accurately displays the orientation of the expanded construction which consists of the strands l4 bounding the openings 16. Said expanded construction is illustrated in a simplified, diagramatic fashion in FIGS. 1 and 3, but as shown in said enlarged portion of FIG. 3 is actually oriented at an oblique angle to the longitudinal length of the strip 10. That is, the long dimension of each diamond-shaped opening 16 is substantially parallel to the shearing edge 34, and since the shearing edge 34 is at an oblique angle 59 to the length of strip 10, it therefore follows that the long dimension of each diamond-shaped opening 16 is also at an oblique angle 59 to the length of strip 10.

A latitude of modification, change and substitution is intended in the foregoing disclosure and in some instances some features of the invention will be employed without a corresponding use of other features. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the spirit and scope of the invention herein.

I claim:

1. A method of producing an expanded metal strip comprising the steps of guiding an elongated metal strip along a feed path with a guide means positioned adjacent said feed path in guiding relation to a guided edge of said strip, progressively producing sheared slits in said strip starting at a location adjacent said other unrein a portion of the width of said strip. 

1. A method of producing an expanded metal strip comprising the steps of guiding an elongated metal strip along a feed path with a guide means positioned adjacent said feed path in guiding relation to a guided edge of said strip, progressively producing sheared slits in said strip starting at a location adjacent said other unrestrained edge of said strip, said slits being spaced a select distance from and defining a solid border along said guided strip edge and being oriented at an angle of 20* to said feed path, and simultaneously with the production of each angularly oriented slit in said strip pushing open the same to provide said expanded construction to said strip, said direction of pushing being toward said unrestrained edge of said strip whereby said strip is simultaneously sheared and expanded only in a portion of the width of said strip. 